Analysis of data on $B$ decays into two light vector mesons

TL;DR

This paper compares experimental data on $B$ decays into two light vector mesons with QCD Factorization predictions, highlighting areas of agreement and discrepancy, and providing new predictions for unmeasured observables.

Contribution

It offers an updated comparison of theory and experiment in $B$ decays, including new predictions and a self-contained summary of the formalism used.

Findings

Acceptable fit for branching ratios and CP asymmetries.

Discrepancies in polarization fractions for specific decay modes.

Predictions for unmeasured observables.

Abstract

An important experimental effort has been accomplished in recent years in the measurement of rates, polarization and CP observables in $B$ decays into two light vector mesons. On the theoretical side, after a very consistent effort done within the framework of QCD Factorization, the comparison of the theory with the present experimental data has not been updated, to our knowledge. In the present paper we compare this wealth of data to the theory, in tree color-allowed, tree color-suppressed and pure penguin decays, and present predictions for the observables that have not yet been measured in these decays. In our fits we find acceptable values of $\chi^2$ for the branching ratios and for the direct CP asymmetries. However, this is not the case for the longitudinal polarization fractions, essentially due to disagreement between theory and experiment for the modes $B_{d,s}\to K^{*0}\overline{K}^{*0}$ and $B_d \to \rho^+ \rho^-$. Although we rely on previous work by other authors, we summarize the formalism so that the paper is self-contained and its results can be checked.